Magnetic properties of epitaxial Fe dots grown on pre-patterned GaAs substrates

Summary form only given. We demonstrate that high quality epitaxial arrays of Fe dots can be fabricated on prepatterned GaAs[100] substrates and that the hysteresis loops of the dots can be reconstructed from the composite MOKE loop obtained from the whole structure. These loops were then used to analyse the angular dependence and distribution of the switching fields of the dots. Two sets of arrays (500 /spl mu/m by 500 /spl mu/m) of circular dots (fixed diameter 0.21/spl mu/m to 50 /spl mu/m) with an etching depth of 0.1 /spl mu/m were pre-patterned on GaAs[100] substrates by nano-imprint lithography. In the first set the dot separation is twice the dot diameter while in the second set the dot separation is half the dot diameter. 15nm thick epitaxial films of Fe have subsequently been grown on these substrates and the resulting magnetic structures were characterised by ex-situ Magneto-Optic Kerr Effect (MOKE). In general pre-patterning substrates before the deposition of the magnetic material should eliminate defects usually induced during patterning magnetic films and reduce the edge roughness to the intrinsic grain size of the magnetic film.